It will also temporarily guarantee most new debt issued by insured banks and the Federal Reserve will take steps to become the "buyer of last resort for commercial paper".

"These measures are not intended to take over the free market, but to preserve it," Bush said of the government intervention that many economists regard as contrary to the principles of free-market capitalism.

Nine banks have agreed to join the government programme, including Citigroup, Goldman Sachs, Morgan Stanley and Bank of America.

Banks signing up will have to agree to limits on executive pay and other benefits, Henry Paulson, the US treasury secretary, said.

Other banks will have an option to accept the programme, in which the government gets "senior preferred shares" which the treasury says will not give it voting rights.

"Today's actions are not what we ever wanted to do," Paulson said, delivering his comments alongside Ben Bernanke, the Federal Reserve chairman, and Sheila Blair, the head of the government's Federal Deposit Insurance Corp.

"But today's actions are what we must do to restore confidence to our financial system.

"Government owning a stake in any private US company is objectionable to most Americans - me included - yet the alternative of leaving businesses and consumers without access to financing is totally unacceptable.

"When financing isn't available, consumers and businesses shrink their spending, which leads to businesses cutting jobs and even closing up shop."

Al Jazeera's John Terret explained that the plan marked a change in strategy for the US bailout.

Instead of putting all the money into buying illiquid assets held by banks and other companies, the US government was going to do what Eurozone and the British governments had done: take direct stakes in banks.

Our correspondent added that there would be considerably less risk-taking after the government takes a stake in the banks.